Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/64—Heating or cooling preforms, parisons or blown articles
  • B29C49/68—Ovens specially adapted for heating preforms or parisons
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
  • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
  • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
  • B29C2035/0822—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using IR radiation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/4205—Handling means, e.g. transfer, loading or discharging means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/64—Heating or cooling preforms, parisons or blown articles
  • B29C49/68—Ovens specially adapted for heating preforms or parisons
  • B29C49/6835—Ovens specially adapted for heating preforms or parisons using reflectors

Definitions

• the present invention is generally situated in the field of the manufacture of containers, such as bottles, flasks, etc., made of thermoplastic material, such as PET or PEN, by blow molding or stretch blow molding. starting containers or blanks (preforms, intermediate containers) and, more specifically, the invention relates to the phase of heating said blanks carried out prior to the blowing or stretch-blowing step in order to soften and make deformable the plastic material.
• the invention relates to improvements made to ovens for heating parades of blanks, in particular preforms or intermediate containers, made of thermoplastic material, this oven comprising transport means suitable for supporting and moving blanks one after the other. following the others while rotating each of them around its own axis and heating means arranged laterally to the conveying means so as to heat the bodies of said blanks in movement.
• thermoplastic material In order for the stretching process to take place correctly and evenly over the entire body of the blank, it is necessary that all of the thermoplastic material is brought to a temperature sufficient to be softened, without this temperature being excessive to avoid crystallization of the material. This implies that, despite the poor conductivity of the thermoplastic material, a sufficient amount of heat (generated for example in a known manner by infrared radiation) propagates through the whole the thickness of the blank wall (core heating).
• thermoplastic material implies a certain period of time to reach core heating and a reduction of this period by increasing the power of the infrared radiation risks causing crystallization of the surface material of the external face of the wall.
• a solution to the problem must therefore be sought by extending the time of exposure of the thermoplastic material to the heating means.
• An interesting solution may consist in increasing the length of the oven, which, for a given running speed of the blanks, leads to increasing the duration of exposure. It then becomes possible to envisage a reduction in the emission power of the heating means, which is authorized by the fact that the heat necessary time is then allowed to propagate through the thickness of the wall of the drafts.
• This solution certainly entails an additional cost in material for lengthening the oven, but in use it is economical because of the reduction (up to 35%) of the energy required for heat treatment of the blanks.
• the invention proposes an improved solution making it possible to satisfy the expressed need for a longer exposure of the blanks to the heating means while avoiding the various drawbacks of the solutions described above.
• the invention provides an oven for heating blanks, especially preforms or intermediate containers, in parade, of thermoplastic material, this oven comprising transport means suitable for supporting and moving blanks one after the other. while rotating each of them around its own axis and heating means arranged laterally to the conveying means so as to heat the bodies of said blanks in movement,
• the conveyor means are arranged so as to present at least two transport branches extending substantially parallel one to each other and in proximity to one another and in opposite directions of transport, said two branches being traversed one after the other by the blanks, and the heating means being arranged between said two parallel transport branches and arranged so as to bilaterally and simultaneously heat the blanks running in opposite directions respectively on the two transport branches.
• the two branches are, at one of their ends, joined by a loop conveyor section which is situated outside the zone of action of the heating means and which therefore constitutes a zone for thermal stabilization of the blanks .
• each blank passes through the oven at least twice, with an interruption between these two heating phases, which corresponds to the turning path of the conveyor means and which constitutes a stabilization step during which the heat continues to diffuse within the material.
• the duration of the heating is thus doubled, and leads to a heat treatment of the thermoplastic material carried out under optimal conditions providing a homogeneous and central heating of the whole of the plastic material.
• furnace arrangements with two lines for passing objects to be treated on either side of the heating means .
• the two lines of objects to be heated move in the same direction.
• These known ovens make it possible to double the processing capacity, but each object only makes a single journey through the oven. Therefore, the exposure time of each object is not lengthened compared to the exposure time of an object passing through a traditional oven (that is to say to a single file of objects) similarly length.
• the two successive exposures of each object to the heating means can be advantageously accompany by a reduction in the power of the radiation emitted by said heating means, and therefore by a reduction in the electrical power consumed, which is particularly advantageous for the user (tests have shown that the economy obtained, with infrared radiation lamps, reaches or even exceeds 50%).
• the oven comprises two pairs of parallel transport branches with heating means respectively disposed between the two branches of each pair, the four transport branches being connected in series to each other by transport sections looped outside zones of action of the heating means.
• the four transport branches are mutually parallel and preferably that the branches are substantially rectilinear.
• FIG. 1 is a simplified diagram illustrating an arrangement of an oven implementing the provisions of the invention
• FIG. 2 is a simplified diagram illustrating an advantageous example of embodiment of an oven exploiting the provisions of FIG. 1.
• an oven 1 is intended to heat blanks, in particular preforms or intermediate containers, during the procession, made of thermoplastic material such as PET or PEN, such an oven being able to be placed in particular , upstream of a blowing or stretch-blowing installation for the manufacture of containers.
• the oven 1 comprises transport means 2 suitable for supporting and moving blanks (not shown) one after the other while rotating each of them around its own axis.
• these conveyor means can consist of an articulated series or chain of support devices ("turners") capable of supporting the blanks by their neck, at the same time as these support devices are rotated (for example by engagement of a toothed wheel - which is integral with it - with a chain or rack fixed side) so that each blank, at the same time as it is moved, is rotated so that its body is exposed over its entire periphery to heating means 3 disposed laterally to the transport means.
• the conveyor means 2 are arranged so that at least two branches 4, 5 of transport extend substantially parallel to one another and close to each other, having opposite directions of movement.
• the two branches 4, 5 are traversed one after the other (in series) by the blanks as symbolized by the arrows 6.
• the heating means 3 are arranged between the two branches 4, 5 of the transport means 2 and are arranged so as to operate bilaterally and simultaneously heat the blanks circulating in opposite directions respectively on the two branches 4, 5 of the transport means.
• FIG. 1 shows the heating means 3, here in the form of three successive sets 7 of infrared radiation heating lamps.
• the two branches 4, 5 of the means of transport which in a preferred embodiment are substantially rectilinear inside the furnace as illustrated in FIG. 1, are joined to one another, at one end (that on the right in FIG. 1) of the oven 1, by a section 8 of the transport means shaped in a loop.
• the looped section 8 of the means of transport in addition to its function of connection between the branches 4, 5 passing through the oven, also plays the role of stabilization zone allowing the heat to continue to propagate inside the thermoplastic material and avoid excessive heating of the external face of the body of the blanks.
• the furnace 1 is equipped with reflectors 9 arranged opposite the heating means 3, on the other side of the branches 4, 5 of the means of transport.
• each blank passes twice in succession opposite the heating means with an intermediate period of thermal stabilization.
• the same heating time is obtained for each preform with a significant reduction in the power of the heating means and therefore in the electrical power consumed, without increasing the number of heating lamps and without increasing the length useful in the oven - compared to a traditional oven with a single transport line -, while the preforms are heated more evenly and to the core.
• FIG. 1 is schematically illustrated a concrete example of an oven implementing the foregoing arrangements.
• the arrangement illustrated in FIG. 1 consists in doubling (parts A and B) the arrangement represented in FIG. 1, the blanks then making four successive crossings of the furnace - and therefore four successive heatings - interspersed with periods of thermal stabilization.
• the blanks arriving at E are delivered by loading means 10 (such as a clothing wheel) to the transport means 2 constituted in the form of a chain 2, in a closed loop, of support devices.
• the chain 2 then enters part A of the furnace 1 via its branch 4A where the blanks undergo a first heating, then, after passing over the section 8A in a loop, a second heating on the branch 5A.
• the blanks then pass over a connecting section 11, which also defines a thermal stabilization zone, bringing them to the second part B of the furnace in which they follow a similar route: branch 4B with heating, section 8B in a loop with thermal stabilization, branch 5B with heating.
• a section 12 brings the blanks to unloading means 13 (such as a "stripping" wheel) where they are detached from the chain 2 support devices (which returns to the means of loading 10) and are evacuated in S to, for example, a blowing or stretch-blowing unit. Because the unloading means 13 are not immediately attached to the outlet of the oven, the section 12 also constitutes a thermal stabilization zone completing the diffusion of heat within the thermoplastic material.
• unloading means 13 such as a "stripping" wheel
• the four branches 4A, 5A, 4B, 5B can be mutually parallel, so that it is possible to constitute an oven of simple and compact arrangement, with less heat loss.

Landscapes

• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Tunnel Furnaces (AREA)
• Containers Having Bodies Formed In One Piece (AREA)
• Cookers (AREA)
• Details Of Cutting Devices (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
• Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (11)

Cited By (2)

Families Citing this family (10)

Citations (6)

Family Cites Families (1)

• 2002
  • 2002-12-12 FR FR0215715A patent/FR2848495B1/fr not_active Expired - Fee Related
• 2003
  • 2003-12-10 PT PT03815112T patent/PT1575755E/pt unknown
  • 2003-12-10 EP EP03815112A patent/EP1575755B1/fr not_active Expired - Lifetime
  • 2003-12-10 WO PCT/FR2003/003661 patent/WO2004062885A1/fr active IP Right Grant
  • 2003-12-10 AU AU2003296808A patent/AU2003296808A1/en not_active Abandoned
  • 2003-12-10 ES ES03815112T patent/ES2295700T3/es not_active Expired - Lifetime
  • 2003-12-10 DE DE60316839T patent/DE60316839T2/de not_active Expired - Lifetime
  • 2003-12-10 AT AT03815112T patent/ATE375242T1/de not_active IP Right Cessation
  • 2003-12-10 JP JP2004566122A patent/JP4275628B2/ja not_active Expired - Fee Related
  • 2003-12-10 CN CNB2003801056080A patent/CN100526050C/zh not_active Expired - Fee Related
  • 2003-12-10 US US10/537,053 patent/US7291811B2/en not_active Expired - Fee Related

Patent Citations (6)

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